The present invention relates to a pipe system of a suction central cleaning installation and more particularly to the ducts located between a suction station and the suction or exhaust openings located in the different rooms of a building. These ducts can be fixed to the walls or floors of the rooms of the building. The mobile and visible part of the cleaning installation can be connected, as desired, to any one of the said suction openings. Thus, during the cleaning operation, apart from the means constituted by the conventional suction hose having a flexible part and a rigid part for gripping, there is only a need for appropriate end fittings for connecting the tube into the suction opening. Each opening is provided with a sealing device and is equipped with an incorporated contactor electrically connected to the motor of the suction turbine, so that by simply introducing or withdrawing the suction hose, said turbine is electrically stopped or started.
For such installations, which presupposes the presence of an electrical control of the suction group at each opening located in the different rooms of the building, it is necessary to connect the individual electrical controls to the suction station by an electric cable. For safety reasons, preferably use is made of low voltage cables (24 v). However, during the installation of the suction system, this makes it necessary to pass into the walls or floors of the building central electrical wiring and each opening must be individually connected thereto. Such an operation is fastidious and onerous, because it requires specially trained personnel on site.
The attached FIG. 1, seen in cross-section, shows a building 10 (e.g. a detached house) equipped with such a central suction cleaning system. The latter comprises a suction station 12 connected by a certain number of tubes 14 to openings 16. There is an opening 16 in each room. Thus, when it is wished to clean a room by suction, it is no longer necessary to drag or haul a heavy, cumbersome suction or exhaust fan. It is merely necessary to open the cover closing opening 16 located in the corresponding room and to connect a flexible tube to said opening. The means 18 to be manipulated is a conventional suction hose having a rigid part 20 for gripping and a flexible part 22, whereof the end opposite to the rigid part 20 is introduced into the opening 16 with the aid of an appropriate end fitting 24. In order to simplify the installation of the electric wiring, it has been proposed to pass the conductors along tubes and couplings.
U.S. Pat. No. 3,465,111 describes such a system in which the cables are in the form of small diameter unifilar conductors. The couplings comprise a female part having a certain number of conductive material plates. In order to bring about connection, the insulant on the conductors at the end of a tube is torn away and the end thereof is introduced into the coupling in order that the bared or stripped part of the conductors comes into contact with the plates.
Although this solution makes it possible to reduce the overall dimensions of the installation by passing the conductors along tubes, it still suffers from a certain number of disadvantages. The realization of such a system is complex and consequently costly. Moreover, stripping is a difficult operation and the contact between the stripped conductor and the plates of the couplings is not reliable, because there is little surface in contact. Finally, the housing of the conductors leads to the formation of a protuberance within the tubes and said protuberance is subject to abrasion by foreign bodies sucked into the installation.